Pin-cylinder lock



Patented Feb. 2d, 192%.

are Wage WILLIAM 'I. CO'NEY, OF NEW BRITAIN, CONNECTICUT, ASSIGNOR TOTHE AMERICAN HARDWARE CORPORATION, OF NEW BRITAIN, CONNECTICUT, ACQEEORATION OF CONNECTICUT.

PIN-CYLINDER LOCK.

Application filed June 27, 1922. serial No. 571,312.

To all whom it may concern:

Be it known that I, WILLIAM T. Comer, a. citizen of the United States ofAmerica, residing at New Britain, Connecticut, have invented a new anduseful Improvement in Pin-Cylinder Locks, of which the following is aspecification.

My invention relates to improvements in so-called pin tumbler locks. Theobject is to provide simple and inexpensive means for preventing thelook from being rendered ineffective by drilling from the front throughthe several pin tumblers. Heretofore such locks have been provided insome instances with a special armor piece of hard material, such assteel, fixed in the cylinder or face plate at the front of the lock, thefunction of said armor being to prevent a drill point from beingsuccessfully used in drilling through the several pins. My inventionaccomplishes the same object, but entirely omits the aforesaid separatearmor construction and the time, expense and labor of making andattaching the same to the cyl-- inder.

In the accompanying drawings Fig. 1 is a vertical longitudinal sectionthrough the center of a pin cylinder lock constructed to embody myinvention.

Fig. '2 is a section on the line 22 of Fig. 1.

1 represents the main body, or cylinder, of the look. 2 represents theusual rotatable plug mounted in the body 1. 3 represents the usual fiatkey employed in such locks. Mounted within the cylinder and plug aresocalled pin tumblers, each tumbler being made of two or more pieceswhereby, when said tumblers are properly positioned by a correctlydesigned key, the adjacent ends of each pair of tumbler pieces willregister with the line of division between the cylinder and the plug 2(as shown in Fig. 1), whereby said plug 2 be turned. When the icy iswithdrawn the pin tumblers are projected downwardly, so that portionswill extend across said line of division and thus positively lock theplug 2 against rotation in the manner Well known in looks of this type.

Grdinarily all such pin tumblers are made from relatively soft material,such as brass, which is easily drilled. My invention comprehends makingone of said tumblers of hard metal, such as steel, which is not easilydrilled, and which will therefore tend to deflect, or break, the pointof a drilling tool, thus safeguarding the lock against this form ofattack. The particular tumbler which is made of steel in the presentcase is shown as the outer tumbler and comprises the socalled guardportion 4 and the driver portion 5. 6 represents the usual tumblerspring.

While l have shown in the drawing the outermost tumbler as the one to bemade from hard metal, 1 donot desire to be limited in this respect inevery case, as the same end could be accomplished, only, perhaps, in aless satisfactory de ree, by making one of the other tumblers or steelor the like. In the form shown I also, by preference, reduce the lengthof the bore in which the guard pin t stands relatively to the length ofthe bores for the other pins, whereby said guard pin will partake ofonly a very short movement. In Fig. 1 the guard pin is shown as properlyelevated to unlock the plug 2, whereas, in Fig. 2, this pin tumbler isshown in its lowermost osition, in which it would appear when the key 3is removed.

By comparison with a lock in which a special armor piece is provided ina fixed position in front of the line of pin tumblers, it is at onceapparent that my new means for guarding against the drilling of the lockP vastly cheaper, since involves merely making one of the pin tumblersof hard metal instead of relatively soft metal, as before, whereby saidpin tumbler itself will perform a double function, namely, a pin tumblerlocking function and a guard function. The matter of assembly involvesno cost, as that is completely absorbed in the cost of assembling thetumblers.

What I claim is:

In a pin tumbler look, a cylinder, a plug rotatable there n, said plughaving a key slot, said plug and cylinder hea ing pin pas sages arrangedto hold plurality of pins, one of the pin passages in said plug beingshorter than the others, and guard pin of hard metal movable in the saidshorter passage for the purposes described.

WILLIAM T. CONEY.

